The cause of thyroid cancer is unknown, although genetics may play a role.

Genes control the functions inside a cell. Special genes control how cells divide and grow. Cancer occurs when the damaged genes stimulate the cell to multiply out of control. The exact cause for this damage is unknown.

Examples:

• DNA
• Genes on chromosomes
• Cancer cells
• Cancer cell division

Cancer cells can develop from any of the cells in the thyroid gland. The cells can spread through the lymphatic system or the bloodstream.

Examples:

• Cancer cell metastasis
• Where cancer can spread